Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 4 5 2004 10.5194/acpd-4-5019-2004 http://www.atmos-chem-phys-discuss.net/4/5019/2004/ http://www.atmos-chem-phys-discuss.net/4/5019/2004/acpd-4-5019-2004.html http://www.atmos-chem-phys-discuss.net/4/5019/2004/acpd-4-5019-2004.pdf 5019 5044 2004-09-07 Early unusual ozone loss during the Arctic winter 2002/2003 compared to other winters F. Goutail florence.goutail@aerov.jussieu.fr J.-P. Pommereau F. Lefèvre M. Van Roozendael S. B. Andersen B. A. Kåstad Høiskar V. Dorokhov E. Kyrö M. P. Chipperfield W. Feng Service d’Aeronomie, CNRS, Verrières le Buisson, France Belgian Institute for Space Aeronomy (BIRA), Brussels, Belgium Danish Meteorological Institute, Copenhagen, Denmark Institute for Air Research, Kjeller, Norway Central Aerological Observatory, Moscow, Russia Finnish Meteorological Institute, Sodankylä, Finland School of the Environment, University of Leeds, Leeds, UK Total column ozone reduction in the Arctic is evaluated each winter since 1993/1994 by the transport method (3-D CTM passive ozone minus measurements). The cumulative loss from 1 December to the end of the season ranges from 5–10% during warm winters like 1998/1999, 2000/2001 and 2001/2002 up to 30%–32% during cold winters like 1994/1995 and 1995/1996. The 23% cumulative loss observed during the winter 2002/2003 is similar in amplitude to the 20–24% measured in 1996/1997 and 1999/2000 but the timing is different. It started unusually early in December after the occurrence of very low temperature at all stratospheric levels between 550 K and 435 K allowing PSC formation and thus chlorine activation. The early ozone loss of 2002/2003 is well captured by current 3-D CTM models.